高纯氢氧化铈生产工艺研究

以硝酸铈液为原料，双氧水为氧化剂，氨水为中和剂，在弱酸性介质中（pH=5～6）生产高纯氢氧化铈。研究了双氧水与氨水物质的量比、分解温度、保温分解时间等条件对产品的硝酸溶解性及氧化率的影响。同时分析了沉淀完全pH变化对产品中氧化镁杂质含量的影响。确定了优化条件：双氧水与氨水物质的量比为1.20～1.25，分解温度大于92 ℃，保温分解时间大于40 min，沉淀完全pH为8.5～9.0。用此方法制备的高纯氢氧化铈产品合格率达到99.98%。

Study on production process of high purity cerium trihydroxide

High purity cerium hydroxide[Ce(OH)4] was prepared in weakly acidic medium(pH at 5～6) with cerium nitrate as raw material,H2O2 as oxidant,and NH3·H2O as neutralizer.Influences of factors,such as amount-of-substance ratio of H2O2 to NH3·H2O,decomposition temperature,and time of decomposition with heat preservation on nitric acid solubility and oxidation rate of the product were studied.Meanwhile,the impact of the changing of pH after precipitated totally on MgO impurity of the product was also analyzed.Optimized conditions were obtained:n(H2O2)/n(NH3·H2O)=1.20～1.25;decomposition temperature was higher than 92 ℃;decomposition time with heat preservation was more than 40 min;and pH was at 8.5～9.0 after precipitated totally.Qualified high purity Ce(OH)4 products can archeive 99.98% with this method.